Engineered crops -- bringing us stronger weeds but fewer butterflies?

A monarch caterpillar on its host plant, milkweed (Los Angeles Times )

With Proposition 37 -- to label genetically engineered food -- on the November ballot in California, there's obviously a raised level of debate about whether such food is truly safe for human consumption. The evidence doesn't indicate any harm, but a 2009 editorial in Scientific American complains that too much of the research is controlled by the companies that produce the bioengineered seed. Concerns have been raised about possible allergenicity; on the other hand, some genetically engineered food has been designed specifically to remove properties that cause allergic reactions.

The bigger concern on The Times' editorial board has been whether genetically engineered crops can cause environmental damage, and here the evidence is stronger that there is a problem. When the No on 37 group met with the editorial board last week, they didn't deny that the crops are contributing to the emergence of herbicide-resistant weeds -- specifically, resistant to glyphosate, better known by the trade name Roundup. Among the more prominent forms of engineered crops are the "Roundup ready" varieties that are meant to withstand the popular herbicide so that farmers can spray pest plants without harming the food plants. Their reaction was that new crops would be resistant to other weedkillers -- Dow Agrosciences, for example, is seeking approval for a bioengineered corn that is resistant to the herbicide 2,4-d.

I'm not convinced, though, that creating weeds that can resist more and more herbicides is the answer.

A new study out of Washington State University adds to the body of evidence about the possible environmental effects of crops designed to withstand spraying. Ultimately, the peer-reviewed research found, the result has been further reliance on herbicides in greater amounts:

"Contrary to often-repeated claims that today’s genetically-engineered crops have, and arereducing, pesticide use, the spread of glyphosate-resistant weeds in herbicide-resistant weedmanagement systems has brought about substantial increases in the number and volume ofherbicides applied. If new genetically engineered forms of corn and soybeans tolerant of 2,4-D are approved, the volume of 2,4-D sprayed could drive herbicide usage upward by anotherapproximate 50%."

This follows research earlier this year that linked the rise of genetically engineered crops to the dramatic decline of the monarch butterfly in the Midwest. The study by researchers from the University of Minnesota and Iowa State University found that as genetically engineered crops became common in the Midwest, the monarch's population in that area plummeted by 81%. The possible reason: more thorough spraying with herbicides killed off most of the milkweed, a weed to farmers but the only host plant of the monarch. Although the research established a clear correlation, its unclear how much of the problem was caused by the crops. Monarchs cover wide swaths of territory in their impressive migration and there were other factors, such as deforestation, that might have contributed.

Most of the corn and soybeans grown in this country are genetically engineered. Is the federal job doing an adequate job of monitoring the effects? It appears not.